The present invention relates to a map data architecture platform that can be used in on-road vehicles, such as automobiles, trucks, buses, and so on, and in particular the present invention relates to a map data architecture platform that supports advanced driver assistance systems provided in on-road vehicles.
Advanced driver assistance systems (xe2x80x9cADASxe2x80x9d) have been developed with the intent of improving the safety, comfort, efficiency, and overall satisfaction of driving. Examples of advanced driver assistance systems include adaptive headlight aiming, adaptive cruise control, and adaptive shift control. Adaptive headlight aiming adjusts the vehicle""s headlights, i.e., width, rotational angle, elevation angle, and brightness, based on the curvature of the road ahead of the vehicle, tilt, elevation change, and other factors. Adaptive cruise control maintains and/or resumes a set speed or safe following distance from other vehicles at slower than the set speed based on data about vehicle speed, nearby vehicles and other obstructions, type of road traveled (motorway vs. local road), road curvature, tilt, elevation, and other factors. Adaptive shift control adjusts the gearing and shifting of automatic transmissions based on sensor data about vehicle speed, engine speed, road curvature, tilt, elevation, and other factors. There are other advanced driver assistance systems in addition to these.
These advanced driver assistance systems use a variety of sensor mechanisms in the vehicle to determine the current state of the vehicle and the current state of the roadway in front of the vehicle. These sensor mechanisms may include radar and vision-oriented sensors, such as cameras. Although radar and vision-oriented sensors are important components of advanced driver assistance systems, these components have limitations. The range and/or accuracy of radar or vision-oriented sensors can be affected by certain environmental conditions, such as fog, heavy rain or snow, or snow-covered roads. Moreover, radar and vision-oriented systems do not reliably detect certain useful road attributes, such as speed limits, traffic signs, bridge crossings, etc. Further, radar and vision-oriented sensors cannot xe2x80x9cseexe2x80x9d around comers or other obstructions and therefore may be limited under such circumstances.
One way to address the limitations of radar and vision-oriented systems is to use digital map data as an additional component in advanced driver assistance systems. Digital map data can be used in advanced driver assistance systems to provide information about the road ahead. Digital map data are not affected by environmental conditions, such as fog, rain or snow. In addition, digital map data can provide useful information that cannot reliably be provided by vision-oriented systems, such as speed limits, traffic and lane restrictions, etc. Further, digital map data can be used to determine the road ahead of the vehicle even around comers or beyond obstructions. Accordingly, digital map data can be a useful addition in advanced driver assistance systems.
Although digital map data can be used as an additional component in advanced driver assistance systems, issues remain to be addressed before digital map data can be widely used for such purposes. For example, there is a need to efficiently handle the relatively large amount of digital map data required for advanced driver assistance systems. In addition, different advanced driver assistance systems require different types and quantities of digital map data and therefore there is a need to provide those digital map data needed by the various advanced driver assistance systems.
To address these and other objectives, the present invention comprises a method and system for use by driver assistance systems installed in a motor vehicle to continuously provide such systems with updated data about paths along roads onto which the motor vehicle can travel from a current position of the motor vehicle as the motor vehicle travels along said roads. The method includes accessing a database that contains data that represents segments of roads and intersections of a road network located in a geographic region in which the motor vehicle is traveling and determining one or more paths along roads onto which the motor vehicle can travel from a current position of the motor vehicle. Each path is extended out to a threshold. Data representing these paths are provided in an organized data structure for use by the driver assistance systems. The data representing the paths include data about road geometry, road attributes, and objects along each path.